1. Field of the Invention
This invention relates to a recording instrument which performs recording by use of an ink (recording liquid), and particularly to a recording instrument that has an ink supplying system with a liquid contacting surface subjected to ink affinity imparting treatment with a compound having hydrophilic groups or a dye solution. 2. Description of the Prior Art
Recording instruments of the system which performs recording by contacting directly an aqueous ink with a material to be recorded on such as paper, are generally so called writing implements such as a fountain pen, felt pen, aqueous ink charged ball point pen(hereinafter referred to as an "aqueous ball pen"), etc. Recently, an ink jet recording system wherein recording is performed by ejecting ink according to various systems has appeared, and it is attracting attention as a recording system capable of high speed and multi-color printing.
These recording instruments are constituted basically of a recording means for attaching ink to the material to be recorded on by various systems, an ink storage means for storing ink and an ink supplying system for supplying ink from the storage means to the recording means.
The ink supplying system is an important part for supplying ink continuously and momentarily to the recording means during recording, thereby smoothly effecting recording with ink. Generally speaking, the ink supplying system comprises a liquid chamber provided for the purpose of storing the ink supplied from an ink storage means such as an ink cassette and an ink passage for conveying ink through said liquid chamber to the recording means. In some cases, the ink storage means and the ink supplying system are integrally combined.
The material constituting the ink supplying system for the above recording instrument is required to be excellent in ink resistance at the contacting surface with the ink, and moreover to have characteristics necessary for continuous and smooth conveying of ink without stagnation of ink during recording. In addition, the material is also required to have characteristics for manufacturing such as easy working, molding and assembly, and the material is also chosen from these standpoints.
In the prior art, various resins, glasses and metals have been utilized as the constituting members. Several problems have been pointed out for these materials. For example, when the ink is supplied again to the recording means after stopping of recording for a long time or briefly, partly because the air bubbles tend to the attached at the liquid contacting surface of the ink supplying system with ink, ink discharging from the recording means may become unstable or discharging of ink may be interrupted sufficiently to bring about inability of ink discharging.
Such problems in ink supply are likely to occur particularly when the ink is used up and new ink is filled again, or when there is no presence of ink wholly or partially in the ink supplying system due to evaporation of a part of the ink solvent during interruption of recording for a long term. Also in an ink jet recording device, some problems occur. For example, when the ink in the ink supplying system is used up, it may be sometimes difficult to supplement the ink up to the discharging orifice, or even when filled according to an aspirating operation, air bubbles may be attached on the liquid contacting surface of the ink supplying system whereby no uniform filling throughout the whole ink supplying system is possible. As a result, troubles such as interruption of ink discharging or unstable ink discharging may be brought about during recording.
The above troubles in ink supply are observed particularly when a polymeric material such as polyethylene, polyester, silicone resin is used for the liquid contacting surface with ink of an ink supplying system in a recording instrument which performs recording with the use of ink. Its cause may be estimated to be based on insufficient wettability (ink affinity) of these constituent members of the ink supplying system.
As a method for solving this problem, modification treatment of the liquid contacting surface of the constituent member of the ink supplying system with ink is practiced. As general treatment methods, there may be employed, for example, a chemical treatment method in which treatment is carried out by using a solution of a powerful oxidizing agent such as K.sub.2 Cr.sub.2 O.sub.7 -H.sub.2 SO.sub.4 and a physical treatment method by plasma treatment. The chemical treatment using a solution of a powerful oxidizing agent is dangerous, and further a significant cost is required for disposal of wastewater, thus involving much problems in aspects of safety and economy. On the other hand, according to the physical treatment by plasma treatment, low temperature treatment may be possible within a short time. For this reason, this method is also applicable even for an organic material with low melting point or transition point. Further, since it is a dry process, it is not necessary to conduct washing with a solvent and drying. In spite of these advantages, treatment of the inner wall surface of a slender and long tube or a material having a complicated shape is difficult, and the recording apparatus per se becomes very expensive. Thus, practical problems in applying this treatment method are involved. In particular, the member to be used in the ink supplying system for an ink jet recording device cannot be applied with sufficiently uniform treatment and therefore the physical treatment is not suitable for such a member.
The present invention has been accomplished as the result of extensive studies in view of the problems as discussed above.